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Voter concordance, simple majorities, and group decision methods
Author(s) -
Fishburn Peter C.
Publication year - 1973
Publication title -
behavioral science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 45
eISSN - 1099-1743
pISSN - 0005-7940
DOI - 10.1002/bs.3830180505
Subject(s) - simple (philosophy) , concordance , preference , statistics , mathematics , mathematical economics , order (exchange) , point (geometry) , selection (genetic algorithm) , econometrics , majority rule , group (periodic table) , economics , computer science , artificial intelligence , chemistry , organic chemistry , medicine , philosophy , geometry , epistemology , finance
This paper examines the effect of the degree of agreement among voters' preferences, as measured by the Kendall‐Smith coefficient of concordance, on (1) the likelihood that one decision alternative will have a simple majority over every other alternative and (2) the propensity of the Borda and Copeland selection methods to give common winners. The Borda method determines the winners by maximum point total when uniformly decreasing points are awarded to the alternatives in each voter's preference order. The Copeland method determines the winners by the maximum number of other alternatives that each alternative defeats by simple majority. The general trend for (1) is an increase in the probability of a simple majority winner with an increase in voter concordance. A similar trend is observed for (2) when agreement is measured by the percent of cases in which the Borda winners are identical to the Copeland winners. However, when agreement for (2) is measured by the percent of cases in which some Borda winner is also a Copeland winner, the best agreement is obtained when there is either extreme voter disagreement or extreme voter agreement.